DiscardCtrl() after MakeMovableCtrl() brings to an error

Question

I found a problem involving DiscrdCtrl() and MakeMovableCtrl() functions.
Now I've been able to reproduce it in the simple example I attached: you can see it following these steps
press "Duplicate "Roundness factor"" button and this control is duplicated
press "Discard "Roundness factor"" button and the duplicated control is discarded
for the second time press "Duplicate "Roundness factor"" button and this control is duplicated
for the second time press "Duplicate "Roundness factor"" button and you will see the error "Attempt to free pointer to memory not allocated by malloc() or calloc()"
after I found this kind of errors in my large application, they produced a FATAL error in other parts of my code.
I see this issue both with CVI 2009SP1 and CVI 2010.
Could you help me finding a way to fix this?
Vix
In claris non fit interpretatio
Using LV 2013 SP1 on Win 7 64bit
Using LV 8.2.1 on WinXP SP3
Using CVI 2012 SP1 on Win 7 64bit, WinXP and WinXP Embedded
Using CVI 6.0 on Win2k, WinXP and WinXP Embedded
Attachments:
movectrl.zip ‏13 KB

Answer 1

Hi Vix,
The function InsertPanelAsTabPage makes a copy of the panel, and of all the controls in it. Therefore, what I said before about DuplicateCtrl and DuplicatePanel also applies to InsertPanelAsTabPage: you must recreate the custom control after you copy it. I modified both instances in your code where you were calling InsertPanelAsTabPage:
int main (int argc, char *argv[])
    DeleteTabPage (movableCtrlPanel, MOVABLE_TAB, 0, 1);
    InsertPanelAsTabPage (movableCtrlPanel, MOVABLE_TAB, 0, panelTOinsert);
    GetPanelHandleFromTabPage (movableCtrlPanel, MOVABLE_TAB, 0, &TabViHndl);
    InstallCtrlCallback (TabViHndl, TOINS_NUMERIC, NULL, 0);
    MakeMovableCtrl (TabViHndl, TOINS_NUMERIC, "", 1, 1, 1, 0);
    SetMovableCtrlAttribute (TabViHndl, TOINS_NUMERIC, MOVECTRL_ATTR_CTRL_MOVABLE, 1);
    SetCtrlAttribute (movableCtrlPanel, MOVABLE_TAB, ATTR_CTRL_INDEX, 0);
int CVICALLBACK Discard (int panel, int control, int event,
        void *callbackData, int eventData1, int eventData2)
    int TabViHndl;
    switch (event)
        case EVENT_COMMIT:
            DeleteTabPage (movableCtrlPanel, MOVABLE_TAB, 0, 1);
            SetCtrlAttribute (panel, MOVABLE_DUPL, ATTR_DIMMED, 0);
            SetCtrlAttribute (panel, MOVABLE_DISC, ATTR_DIMMED, 1);
            InsertPanelAsTabPage (movableCtrlPanel, MOVABLE_TAB, 0, panelTOinsert);
            GetPanelHandleFromTabPage (movableCtrlPanel, MOVABLE_TAB, 0, &TabViHndl);
            InstallCtrlCallback (TabViHndl, TOINS_NUMERIC, NULL, 0);
            MakeMovableCtrl (TabViHndl, TOINS_NUMERIC, "", 1, 1, 1, 0);
            SetCtrlAttribute (panel, MOVABLE_TAB,    ATTR_CTRL_INDEX, 0);
            break;
    return 0;